This invention relates to the art of fluid measurement, and more particularly, to apparatus for producing an output directly proportional to the ratio of the densities of two gases.
The word "gravity" is hereby defined for use herein and for use in the clamis to mean either the ratio of the densities of two fluids or the ratio of the density of a gas of any type to the density of air at the same temperature and pressure. As will be explained hereinafter, the gravity of a gas is otherwise substantially independent of temperature and pressure.
In the past, it has been practice to measure the gravity of a gas by loading a gas tight cylinder with a gas and placing it on a balance with a gas tight cylinder of air. This apparatus is expensive and combersome to use. Moreover, gravity is obtained by performing a batch process which cannot run continuously with flowmeter apparatus to indicate instantaneously what the rate of volume flow and the total volume flow in a pipeline is.